The invention relates to method for the dimensional quality control of cast parts, more particularly such a method used for determining the quality of such cast parts having aeronautical applications.
As is well-known, quality control methods for ascertaining the quality of cast parts are applied to both the rough, or as cast, workpiece as well as to the finished workpiece. Typically, after the workpiece has been cast, it must undergo further machining operations to be brought into its final dimensions.
The known quality control methods typically comprise two steps: the step of checking the appearance of the workpiece by looking for burns, inspecting the surface quality for both the external surface of the workpiece as well as any passageways or orifices; and the step of checking the dimensions of the workpiece, either by manually measuring the dimensions, such as with a caliber, depth gauge, etc., or by using a template or the like.
The known quality control steps are usually carried out on the first workpieces produced by a new manufacturing run. Indeed, the initial parts may be subjected to a complete dimensional check, which may include cutting the part open to inspect any interior dimensions. Once the inspection has been satisfactorily completed, it is performed only on randomly selected manufactured workpieces.
To date, such quality control checks have been carried out entirely manually. The manual operations, which may include spot painting to emphasize markings previously applied by an operator with a scriber or a compass, are laborious and consume large amounts of time of skilled personnel. The steps may include: Placing the workpiece at the beginning of the manufacturing run; tracing outer or remote segments to insure that workpiece did not warp from any previous thermal treatment; tracing the axes and the bore hole framing lines in one plane; tipping the part onto another plane and repeating the above operations; and tracing and measuring several shapes.
Such time consuming operations cause production delays, thereby increasing the manufacturing costs of the workpiece. Typically, such quality control checks on a rough, as cast workpiece may take several weeks.